1. Field of Invention
This invention relates to float tubes commonly used in fishing, specifically to an improved foot fin for propelling a float tube.
2. Description of Prior Art
Most float tube fins are similar in design to the foot fins used by swimmers and divers. They operate by movement of the user's legs and feet in a "flutter kick" which propels a float tube to the rear (backward). This direction is opposite to the direction a float tube user normally wishes to move in pursuing rising fish, or in moving to other locations. Efficiency of the prior art fins is low. Use of them in traveling a distance is strenuous and tiring.
The forward extension of the fin blade limits normal foot movement, creating a risk of falling while walking with the fins on. Walking in marginal water to enter or exit a body of water is particularly hazardous, for in addition to the clumsiness of the protruding fin and the restriction of movement and visibility caused by the float tube, the walker has to overcome the water's resistance on the fin with each step. As a consequence, most users of forward extending prior art fins walk backward to enter and exit the water. Walking backward with a bulky float tube in place creates a danger of falling and injury.
The process of donning and removing a ring-shaped float tube while wearing the forward extending prior art fins is also difficult and hazardous, as described:
(a) The bulk and shape of a float tube limits movement, necessitating that the fins are attached to the user's feet prior to donning the float tube. PA1 (b) With the float tube laying flat on the ground the user balances on one foot while stepping over the circumference of the tube with the other foot, inserting said other foot into the leg opening of the float tube seat. PA1 (c) Thus straddling the tube, the user shifts his/her balance to the foot now inside the tube, lifting the opposite (first said) foot over the tube, to insert it also into the leg opening of the seat. PA1 (d) At this point balancing is especially difficult, presenting a danger of falling. The forward extension of the fin, its general configuration and size, and the constriction of the seat makes it awkward to insert both feet into the leg opening of the float tube. Balancing is especially difficult while bending over to maneuver the unwieldy tube into position to facilitate inserting the fin of the second foot into the leg opening. PA1 (e) Removal of the float tube is the reverse of the process of donning it. PA1 (a) to provide an effective float tube fin for forward propulsion, in the direction which the user faces; PA1 (b) to provide a more efficient fin, using less energy for movement; PA1 (c) to provide a less cumbersome fin, for greater ease in the movements of donning and removing a float tube; PA1 (d) to provide a retractable fin allowing the user to walk in a normal manner, reducing the danger of falling and injury; PA1 (e) to provide a simple, easy to operate, latching device to secure the retractable fin in both the extended and retracted positions; PA1 (f) to provide a fin which in use is located below the user's foot, as a longer extension of the user's leg, thereby creating greater leverage and thrust; PA1 (g) to provide a fin which in use is located below the user's foot, close to the vertical center line of the user's body, eliminating side to side yawing and wasted energy; and PA1 (h) to provide a fin that is universally adaptable to fit a wide range of sizes and types of footgear normally used by float tubers.
Two fins designed to provide a means of forward propulsion of a float tube are currently on the market. Use of either of them compels the user to assume a forced, un-natural position in the float tube. Both prior art forward propelling fins are inefficient in use.
One is based on U.S. Pat. No. 4,664,639 to Schneider (1987) which illustrates a fin to be used by a vertically positioned tube fisherman. The fin described is flexibly attached at the toe to deflect, extending underneath the sole of the fisherman's foot. In actual use, the design and construction of float tube seats places a user in the posture of a person seated in a chair, with his/her legs and feet extended in front. Use of the fin described in this patent requires the user to lean forward against the designed posture of the float tube to position his/her legs in a vertical plane. A currently marketed product based on the aforementioned patent ("KICKAPOO KICKERS") has a fin that is quite stiff and rigid. It does not deflect enough to cause an effective drag against the water. Much of the leg motion in using this fin is wasted in movement to cause water resistance to flex the fin into a position where it could become effective. By the time the fin is extended to this position, the stride has been nearly completed, and little further range of leg motion is left to propel the user. The fin impairs one's ability to walk on uneven surfaces, especially in marginal water on rocky bottoms or where debris has settled to the bottom. The smooth hard lower surface of the fin does not grip uneven surfaces well, adding to the problem of walking in rocky marginal water.
The other forward propelling prior art fin ("PADDLE PUSHERS") also compels its user to assume a forced, upright position to move through the water. This product operates by a hinged fin extending outboard to the side of the user's foot. The fin of this product is too small to create an effective propulsive force. If the product were constructed with a larger fin, thrust from the fin (because of its location outboard of the user's leg and foot) would tend to rotate, or yaw the tube, rather than to be applied in the desired forward direction.. As with U.S. Pat. No. 4,664,639 to Schneider (1987), much of the user's leg motion is wasted in causing the fin to open from its folded position to the extended position where it could be effective.